1. Field of the Invention
The present invention relates to a recording tape cartridge. The recording tape cartridge accommodates a single reel around which a recording tape, such as a magnetic tape, primarily used as a recording/playback medium for a computer or the like.
2. Description of the Related Art
Conventionally, there is known a magnetic tape cartridge constructed such that a magnetic tape used as a data recording/playback medium for a computer or the like is wound on a single reel, and the reel is accommodated in an accommodating case. A leader member, such as a leader pin, a leader tape, or a leader block, is provided to the end of the magnetic tape. The leader member is pulled out from an opening of the magnetic tape cartridge by using pull-out means provided in a drive device, and the magnetic tape fixed to the leader member is wound around a take-up reel in the drive device.
A reel gear is formed annular in the center of the reel lower surface appearing from an opening formed on a lower surface of the magnetic tape cartridge, a drive gear provided on a rotation shaft in the drive device is engaged with the reel gear, and the reel is thereby rotationally driven. Therefore, data can be recorded on the magnetic tape, or data recorded on the magnetic tape can be played back in such a manner that the reel of the magnetic tape cartridge and the take-up reel of the drive device are rotated in synchronization.
Magnetic tape cartridges of the above-described type are characterized in that the accommodating space for preservation can be small, and a large amount of information can be recorded. In addition, as shown in FIGS. 12 to 14, the position of the opening and the type of a door for opening and closing an opening are different depending on the type of the leader member. More specifically, as shown in FIG. 12, with a leader pin 110, an opening 118 is formed on a sidewall 114 of an accommodating case 112 formed parallel to the direction of insertion to the drive device (direction of an arrow P). In this case, a door 116 slidably moves in the same direction as the direction of insertion to thereby open and close the opening 118.
However, in the construction including the opening 118 provided on the sidewall 114 of the accommodating case 112, pull-out means of the drive device needs to pull out the leader pin 110 from a left-right lateral direction of the accommodating case 112 via a roundabout route. Therefore, a space for allowing the pull-out means to perform the roundabout access needs to be secured on the side of the drive device, and a complicated mechanism is necessary for driving the pull-out means to perform the roundabout access. This arises a problem in that the drive device needs to be enlarged. Another problem is that the length of the path for pulling out the magnetic tape 108 needs to be increased. Still another problem is that since the door 116 is slidably moved in a state where an upper end portion and a lower end portion thereof are inserted between guide grooves 117, the accommodating-case strengths for the portions of the guide grooves 117 are reduced.
With a leader tape 120, as shown in FIG. 13, an opening 128 is formed on a front wall 124 of an accommodating case 122 formed perpendicular to the direction of insertion to the drive device (direction of an arrow P). In this case, a door 126 is formed to be of a pivot type that pivots in a front direction around the center of a spindle supported in the vicinity of a corner portion of the accommodating case 122. However, in the construction including the opening 128 on the front wall 124 of the accommodating case 122 although the pull-out means of the drive device need not perform the roundabout access, the door 126 largely open in the front direction. Therefore, a space needs to be secured on the side of the drive device in order not to allow any obstruction against the door 126 when the opening 128 is opened. This leads to a problem in that the drive device needs to be enlarged.
With a leader tape 130, as shown in FIG. 14, an opening 138 is formed by diagonally cutting off a corner portion 134 on a front side in the direction of insertion to the drive device. In this case, the opening 138 is directly opened and closed by a leader block 130. However, in the construction thus using the leader block 130 to open and close the opening 138, a problem arises in that the leader block 130 tends to be damaged and stained. Specifically, the leader block 130 is fitted into a reel hub 136 in the drive device, thereby constituting a portion of the reel hub 136. Therefore, even with a damaged portion, a stained portion, or the like that does not cause any problems as long as the leader block 130 is used as a normal door, a case can occur in which, for example, the fitting into the reel hub 136 is caused to be difficult, or a problem is caused in the running of a magnetic tape 108.
Further, since the leader block 130 is just engaged with an end portion of the opening 138, a problem can occur in which the leader block 130 is easily disengaged therefrom in such an event the magnetic tape cartridge is dropped. Still another problem is that since the leader block 130 is large in comparison to the leader pin 110, restrictions regarding the shape of the storage case are increased. Therefore, the leader pin 110 functionally independent of the door is more preferential than the leader block 130 functioning concurrently as the door.